Potentiation of antifungal activity of amphotericin B by essential oil from Cinnamomum cassia

The antifungal activity of the essential oil from Cinnamomum cassia, alone or combined with amphotericin B, a drug widely used for most indications despite side-effects was investigated. The composition of the oil was analysed by GC/MS and characterized by its very high content of cinnamaldehyde (92.2%). The minimal inhibitory concentration (MIC 80%), used to evaluate the antifungal activity against Candida albicans, was determined by a macrobroth dilution method followed by a modelling of fungal growth. The essential oil of Cinnamomum cassia exhibited strong antifungal effect (MIC 80% = 0.169 µL/mL and Kaff = 18,544 µL/mL). A decrease of the MIC 80% of amphotericin B was obtained when the culture medium contained essential oil concentrations ranging from 0.08 to 0.1 µL/mL. The strongest decrease (70%) was obtained when the medium contained 0.1 µL/mL of essential oil. This potentiation of amphotericin B obtained in vitro may show promise for the development of less toxic and more effective therapies especially for the treatment of HIV infection. Copyright © 2006 John Wiley & Sons, Ltd.